Why homes are lost to wildfire

This Forest Service expert says it's as much a sociopolitical problem as it is physical.

The wreckage of a burned structure sits near a surviving home after the 2010 Fourmile Canyon Fire near Boulder, Colorado. The 7,000 acre fire claimed nearly 170 houses in the first days of the blaze. Several of the houses that were saved had properly prepared their land for the potential of wildfire, including building with fire resistant materials as well as preparing defensible, fuel-minimized spaces in the areas surrounding the structure.

Matt Slaby/Luceo

Each year, wildfires claim hundreds of homes throughout the West in what’s known as the wildland-urban interface. This issue roars into the national spotlight every summer as footage of engulfed subdivisions flickers on TVs across the country. National fire suppression budgets reach into the billions of dollars every year, much of that cost associated with protecting homes and structures. But are we approaching the problem from the right angle?

Jack Cohen is a research physical fire scientist with the U.S. Forest Service, based at the Missoula Fire Sciences Laboratory. With four decades of experience, he is a preeminent expert on wildfire and home ignitions, and a founder of the Firewise Communities recognition program, a project of the National Fire Protection Association that helps homeowners protect their property against wildfire.

Years of study have convinced Cohen that the loss of homes to wildfire is as much a sociopolitical problem as it is a physical, on-the-ground problem. Agencies and the public alike approach the issue as a question of fire suppression and control. Cohen, on the other hand, believes that fire is here to stay, and that proper mitigation, awareness and planning can make living with fire a whole lot easier - and safer. HCN contributor Melissa Mylchreest recently spoke with Cohen.

High Country News Every year, wildfires burn hundreds of homes in the wildland-urban interface. From an on-the-ground perspective, can you tell us how this happens?

Jack Cohen Our general perception that a fire comes rolling down a hillside and takes out a neighborhood, like a tsunami or a lava flow, just doesn't fit the physics of the problem. What I've found is that during these big crown fires, the flames pass by quickly, so the radiant heat doesn’t linger in one place very long. That makes them incapable of igniting a structure beyond 100 feet. If we look at all the destruction during wildfires, the principle igniters directly on the house and the immediate surroundings are firebrands, which means that the wildfire may be half a mile away, and we still have neighborhoods burning down. The most recent one with high destruction was the Waldo Canyon Fire in Colorado Springs, where 300-plus houses burned. Most of them were in suburban neighborhoods, not surrounded by trees. And nothing else was burning other than the houses. And that's really common. Which means if we don't take home ignition into account, we're not going to solve anything.

HCN So how do we tackle the home ignition problem?

JC While our attention is on the great big flames and the towering convection columns of a wildfire, we've got firebrands igniting pine needles in the rain gutters, we've got a woodpile on the deck, we've got dead grass or bark mulch right up next to the wood wall. When I go into one of these locations, I find that the wildfire has ceased its extreme activity, hours and hours before houses are actually becoming heavily involved. They've ignited from firebrands and they just sit there with small ignitions, slowly involving enough of the structure to where it can go to flaming combustion.

So, if they're all small, slow ignitions, how is it that our firefighters that can't deal with this? Well, if you have a wildfire displaying extreme behavior, both in its intensity and its growth rate, it potentially can be large enough when it gets close to a subdivision to expose thousands of houses simultaneously. Then we've got a hundred engines that are totally overwhelmed. Which means if we have houses that are highly ignition-resistant, the responding resources can become greatly more effective. Suddenly they don't get overwhelmed, particularly given a different approach to response, and we can begin to tackle the smaller ignitions that do take time to develop.

HCN You mentioned a different approach to response. What does that mean?

JC This problem falls in the no-man's land between structure-fire tactics and wildland fire tactics, so they're both ineffective. An inundation approach, which works with structure fires, with lots of water squirting capability, that doesn't help with small ignitions. As soon as crews start inundating houses, they run out of water. Instead, we need to distribute a small amount of water in many different directions. So rather than having a big Type-One engine that can squirt 1,000 gallons a minute, we have a homeowner with a bucket and a mop and some water.

HCN So, you're saying that homeowners need to play a role in the way we mitigate the risk from fires in WUI?

JC Wildland fires are inevitable. And without homeowner engagement, without their participation in mitigating the problem, firefighters can't be effective. It's continuing a problem to have my own agency, federal agencies in general, and most fire departments in this country that deal with wildland fire issues, not be telling people that by and large, under the conditions that destroy lots of houses, we can't deal with this without your participation. It's about taking responsibility for the condition of your house, before the fire, because nobody else can. And it's not just the material that the house is made of, it's the condition that lends itself to potential ignition. It's a big maintenance issue too.

Really, we need to be educating everybody who lives in (the WUI), or near it, or deals with it. Like Southern California, like Colorado Springs, like Denver. Everyone needs to be aware of how this problem works. Additionally, we're dealing with fire agencies that are very paternalistic and patriarchal. So it doesn't come naturally to involve homeowners. On the other hand, homeowners are expecting to be saved. As a society that has largely gone urbanized, we're more remote from dealing with fire on a personal basis - fewer people smoke, so people aren't even used to a book of matches catching on fire now.

HCN Can you give examples of how homeowners might make their homes less prone to igniting?

JC You don't have to eliminate fire from your property completely, but you have to keep flames from contacting your structure and you have to keep firebrands from having high ignition potential when they land on your house - because they will. Which means all of the fine fuels need to be gone from on and immediately around your house before fire season even starts. All flammable things need to be swept away from your house at least about five feet. The grass needs to be mowed immediately around the structure, but you don' t have to mow an acre.

You don't have to cut all the trees down, you just have to make sure they're not contacting each other, and they're not continuous with the wildland. Make sure fire on the surface can't easily burn up the tree and torch out, because that creates firebrands close to the house. I highly encourage hardwoods around the structure as a shield, they just don't support high-intensity fire, and can become a very, very good radiation barrier.

Absolutely get rid of your flammable wood roof. Make sure firewood is in a sealed crib, or away from the house. Act like the fire department isn't going to show up, because that's the likely scenario.

HCN You say it's a social, perceptional problem. Can you talk a bit about that?

JC Wildfires come from somewhere else onto private property, and now all of a sudden we have this social thing where, oh, it's somebody's fault. It's the Forest Service, it's the BLM, it's the state lands department that's the problem. Well, wildfire is inevitable, and fire is a natural ecological factor. So, how come the message isn't that? This is like tidal surge from a hurricane, volcanoes, earthquakes, severe storms. But we're not doing anything about those. We have this social perception, which has been reinforced by agencies starting shortly after the 1910 fires, that we can control fire, and that's why you're giving us all this money.

Meanwhile, issues are compounded by conflicting mandates on the state and federal level. The states are by and large the last ones to get on board, because they have laws that say they are in charge of protection. They don't have any kind of ecological factors in their plan. It's put it out and protect the resources, whether the resource is houses or the Sula State Forest. On the other hand, it is Forest Service policy that they do not protect structures. So when we see federal firefighters on private lands, they're having to step out of their mandate because of a perception issue.

What I find is that people don't have an appreciation for the natural history of their landscape either. Here in the Missoula valley, people were lighting fires, there were lightning fires, probably every year. I don't think people understand that fire is absolutely an ecological factor that needs to be accepted. So let's celebrate the natural occurrence and be compatible with that. Because control isn't working for us in so many ways, it's just screwing things up, giving us the false impression that somehow or other we don't need to be inconvenienced by this factor of the planet that we live on.

If the firefighters don't scare you off with requests for your dental records, the Sheriff will bum rush you out in a mandatory evacuation.

It's pretty clear that civilians are the LAST thing officials want around during a fire.

We always hear about the unfortunates who get caught and killed, but we hear much less about those who successfully choose to stay and fight, which I would think in certain scenarios is a perfectly rational choice.

Julie Rogers

Apr 05, 2014 11:56 PM

Jack Cohen has, as always, clearly stated the absolute truths about the WUI fire "problem." It does indeed result in large part from the paternalistic approach with which most fire suppression agencies approach the situation. Expecting and welcoming the active involvement of homeowners both before and during fires must become the new norm for fire agencies.

Safety of firefighters and the public is one of five focus areas about which the national Quadrennial Fire Review (QFR) is currently requesting comments at http://qfr.ideascale.com. A comment urging acceptance of the "Prepare, Stay and Defend" model may be found on the site under the header "We need a Paradigm Shift." The deadline for participating in the QFR process is April 11; please add your original thoughts or vote for comments already submitted.

Huge thanks to Jack Cohen for his years of research and insightful writing on WUI fire issues.

Tim Baker

Apr 06, 2014 08:15 AM

The are a lot of problems with "Prepare, Stay and Defend" not the least of which is that far too many are willing to stay and defend but too few are willing to actually prepare. The shelter in place model has been widely used in Australia where it has had some wide success and some significant failures as well. Among the problems are too little water storage, not enough homeowner infrastructure (i.e. pumps and hoses), not enough homeowner knowledge/training, and last minute panic with no viable exit routes that clog arteries hampering firefighter access and safety. Plus, the pressure on firefighters escalates dramatically if there are residents still in the area.

I think a more productive plan would be to drastically alter our developments through zoning and insurance costs to avoid the problem in the first place by minimizing expansion of the WUI and by building more fire resistant houses. The public at large seems to still be operating under the assumption that we should be guaranteed safety regardless of where we build and that mindset is the first thing that needs to be changed.

The best case scenario would be for both sets of ideas to be used -- limit development, mandate fire codes, educate homeowners and build infrastructure to enable shelter-in-place. But what are the likelihoods of those things all occurring in the land-of-the-free-to-be-clueless ?

Rich & Terry Fairbanks

Apr 06, 2014 08:59 AM

Cohen nails it. Don't make your house part of the fuel bed. There are about 10,000 board feet of nice dry lumber in the average house. You must separate that fuel from the fuels in the forest. If you are going to live in our dry western forests, remember what your grade school teacher told you before a test: "neatness counts."

Tyler Rose

Apr 07, 2014 09:51 AM

Not sure if some of the commenters read the entire article or are familiar with all of the work Jack Cohen has put into trying to educate the public and have us all take responsibility for our ourselves. He isn't advocating that the public stay at their houses and defend them when wildfire comes through, he is advocating for some smart planning and making your home less susceptible to fire so that when a fire does occur, it is easier for firefighters to protect your home.

Jack Harvey

Apr 07, 2014 10:31 AM

We live on a ranch that has had more Han a couple of large wildfires come pretty close. One observation is when these fires get large fire fighting resources get stretched very thinly, and you cannot depend on the presence of firefighters to watch your structure. In our last wildfire several of the firefighters lost their own homes while they were working the fire elsewhere.

Personally Prepare, Stay and Defend is the strategy we have adopted, and hope we will never have to use.

Deb Dedon

Apr 08, 2014 05:31 PM

After viewing footage of Waldo Canyon and noticing patterns of burned homes and intact homes, and watching homes burn like paper lanterns, I wondered if more than a wood roof was involved. Cheap wallboard and insulation can be made of cellulose, i.e., recycled paper.

Colin Holloway

Apr 10, 2014 02:16 PM

Thanks Julie,That was quite helpful, a little frighteningly timely and a little clunky & frustrating to manage.Kind of like that other Fed website of....repute....but easier....Be nice if that was a bit better advertised. Only a couple dozen vote-ables that I could find.Definitely, thank you, hope others will get their thoughts in and vote (even if there isn't a "disagree" toggle.

Lyra Cressey

Apr 16, 2014 06:04 PM

Our property and cabin surrounded by public land in Northern California were burned over in an 18,000 acre wildfire last summer. Prior to building, we had the property (and two adjacent private properties) treated for fuels reduction two times in five years by a crew from the local watershed restoration council, and then we did a third round of fuels reduction around the building site ourselves, burning 75 piles. By no means did we clear off the land: it was still beautifully forested and we kept big shade trees--conifers and deciduous--around the building site but we eliminated all ladder fuels and spaced trees nicely.

Before building, we also put in a water system with storage tanks, irrigation, and two fire hydrants with hoses, nozzles, etc. We built with fire in mind: metal roofing, metal siding with enough wood mixed in to make a cozy look without creating a firebomb.

Even before the fire, we were pretty well prepared but, luckily, we had 11 days to prepare even further after the fire began (arson-caused wildfire) before it reached us, and we had a great response for fire prep led by the USFS who used our property as a fire line for their fire fighting efforts on the main wildfire. I know not everyone will have 11 days to prepare but, honestly, 99% of the fire preparation work had already been done and that is something all WUI landowners in fire prone landscapes need to do BEFORE fire season. I won't claim that the arrival of fire was stress-free but it also wasn't too much of a worry and our concern for risk to the cabin was pretty minimal. We chose to stay during the fire despite evacuation orders and we safely participated in the fire fighting effort and preparation alongside the federal firefighters who successfully burned out our property in advance of the wildfire.

We were left with a low intensity burn that further cleaned small fuels off the property, making us even more fire-safe than before. We have some cleanup to do but lost very few large trees and although we had flames 100 feet from the door, it looks beautiful and green now just six months later and the the ecological benefits are great. A majority of our property burned and we're hoping to perform a controlled under burn later this fall to burn off the rest. Fire is part of where we live just like the mountains, blue skies, and wild river.

Jeffe Aronson

Apr 19, 2014 10:49 PM

Our home (and us) survived a 2.5 million acre wildfire in Australia in 2003. We created a defensible space and when the 1,000 kilometer forefront hit us, we managed fine. See photos, video, and our story at shelter-in-place.net

Julie Rogers

Apr 20, 2014 10:51 PM

Huge kudos to Lyra Cressey for her proactive work before and during the fire which impacted her property. Kudos also for telling the story very clearly. Residents throughout the west need to follow her example, and quickly, to make their homes "fire-adapted"; that is, adapted to prepare to survive fires.

I've created a one-page, easy-to-read info sheet summarizing Jack Cohen's research about how homes ignite, for audiences unfamiliar with fire behavior and terminology. Some fire agencies are planning to post it to their websites; in the meantime, if you'd like a copy, email me at julierogers03@ymail.com.